there are a bug with the launcher, when i press "play" nothing happens

first of all, i was playing minecraft on 1.8.9 and every thing was fine. but when 1.9 was released I wasn't able to update it. i don't know why.

I chose "use the lastest version" .but when i press play button it says "loading..." then its return it self to "play" then when i press play again nothing happens.

after that, i tried to delete all the files of ".minecraft" to find out if its work or not. but, sadly the launcher wasn't able to open the game at all

finally, i tried to download the launcher again but unfortunately when i open the website and try to download the launcher or the installer the URL is not working. it says "This webpage is not available"